1. Field of the Invention
The present invention relates to fiber optic coupling and in particular to methods and devices for connecting optical fibers to optical components on semiconductor substrates.
2. Description of the Related Art
FIGS. 1A and 1B show a fiber optic coupling according to known art. A current solution for coupling optical fiber 104 to components on semiconductor substrate 102 involves etching a groove 106 in the semiconductor substrate 102, and aligning the fiber into the groove. A space 107 will exist under the fiber 104. The depth of the groove 106 is selected such that when the optical fiber is positioned in the groove 106, the core of the fiber 104 is correctly aligned with the optical component 108 on semiconductor substrate 102 as shown in FIG. 1B. However, the method described with reference to FIGS. 1A and 1B has at least one significant drawback.
The core diameter of the optical fiber is about 9 μm. The size of the groove needed for alignment is on the order of 12 μm. Accordingly, this method results in a significant use of available space on the surface of the substrate compared to the space used by other components. Additionally, in the event that the coupling involves a cluster of fibers, the total diameter is much greater, requiring a correspondingly larger groove, resulting in even more space occupied.
This integration process requires the alignment of multiple structures at different heights, which is difficult to control. Significant signal loss occurs unless the alignment is accurate and low yields result unless there is very high precision.